Tuning mechanism for radio receiving sets



Fb. 2, 1943.. I A; s. WELLS- 2,310,003

TUNING MECHANISM FOR RADIO RECEIVING SETS Filed Jan. 6; 1941 n s Sheets-Sheet 1 I t i Feb. 2, 1943. A. s. WELLS 2,310,003

TUNING MECHANISM FOR RADIO EECEIVING SETS Fiied Jan. 6, 1941 3 Sheet -Sheet 2 hill/i A. s. WELLS Feb. 2, 1943.

' TUNING MECHANISM FOR RADId RECEIVING SETS Filed Jan. 6, 194; s Sheets-Sheet 5 lllli Patented Feb. 2, 1943 TUNING MECHANISM FOR RADIO RECEIVING SETS Albert S. Wells, Chicago, Ill., assignor to Wells- Gardner & (30., Chicago, 111., a corporation of Illinois Application January 6, 1941, Serial No. 373,263

6 Claims. (Cl. 74-40) The present invention is concerned with certain improvements in an adjustable transmission unit for a radio receiving set tuning mechanism employing a plurality of manuals from any one of which motion may be initiated for transmistuning purposes an operative connection for each 1 manual which is simple, compact, inexpensive,

veasy to produce and assemble, and, above all,

which will lend itself readily, without tools, to adjustment, as desired or required, for setting of its associated tuning elements in resonance with a selected station, all in response to sequential manipulation of the manual and the usual fullrange tuning control which are located at the front of the cabinet containing the usual chassis. In other words, the operation of setting any tuning element into perfect resonance with a desired station may be accomplished solely by manipulations of one of the manuals in conjunction with the control that is provided for all stations. These manipulations of the manuals, however, are not those regularly used for tuning purposes, consequently there is little or no likelihood of any disturbance to, or unsettlement of, an adjustment that has once been made. More particularly, the present improvements are directed to such a mechanism in which one of the transmission elements which is rotatively adjustable is adapted to be releasably locked in a selected rotative position by the application of positive forces which proceed from opposite directions in equal strength whereby to avoid possible de-centering of parts resulting from unbalanced strains or stresses.

It is possible to embody my present invention in various forms all of which, however, are characterized by the same general features of construction and principles of operation. As exemplifications of this invention I have set forth in the accompanying drawings three forms of mechanism wherein the first appears in Figs. 1 to 5, inclusive; the second in Figs. 6 to 17, inclusive; and the third in Figs. 18 and 19. These several figures illustrate embodiments of my invention in the manner following:

Figure 1, which is a transverse sectional view through a framework which supports a tuning mechanism, shows in elevation one of the manuals together with the transmission in connection therewith;

Figs. 2 and 3 are enlarged details in section taken, respectively, on lines 22 and 3-3 of Fig. 1; i

Fig. 4 is a view in perspective of four elements, shown in separated relation, forming the adjust-. able unit in the present transmission;

Fig. 5 is a fragmentary detail of certain of the transmission'elements adjusted to a position different from the showing in Fig. 1, and moved to an opposite extreme position;

Fig. 6, which is a view generally similar to Fig. 1, shows a modified construction of the adjustable transmission unit for a tuning mochamsm;

' Figs. 7 and 8 are enlarged details in section taken, respectively, on lines 1-''! and 8-8 of Fig. 6

Figs 9 and 10 are views in perspective of two elements which, when assembled, are comprised in the transmission unit shown in Fig. 6;

Figs. 11-17, inclusive, which are views similar to Fig. 6, show the same transmission unit thereof in various adjusted and operating positions;

Fig. 18 is a view in elevation of another form which the adjustable transmission unit of my invention may take;

Fig. 19 is a perspective View of the transmission unit shown in Fig. 18; and V Fig. 20 is a transverse section, taken on line 2l 20 of Fig. 18. r v

It will be apparent, as the disclosure proceeds, that the present invention is susceptible of embodiment in many 'diiferent forms of which three, by way of example, are illustrated; They all have in common a transmission unit comprising certain relatively slidable cooperating elements which together releasably look a rotatively adjustable element, free to move without rotation along a fixed path from which a rotative movement is communicated to the tuning device. Such a transmission unit is adaptable, with advantage, for use with a tuning mechanism for radio receiving sets having, inter alia, a series of tuning elements, as the plates a, mounted upon or associated with a tuning shaft 11 which is supported within suitable bearings (not shown). Also I provide a full-range tuning control which may take the form of a beveled gear 0 fast on the shaft b in mesh with a second gear 01 that is carried at one-end of a shaft 15 which extends forwardly through the panel plate e to be operated manually with the aid of a tuning knob l6. Such is the construction illustrated in Fig. l to which reference will further be made in the ensuing description.

The framework for the tuning mechanism comprises the panel plate e through which is a slot 11, a bearing plate 1 parallel with but spaced from the panel plate 6, and a pair of supporting plates of which one, designated as g, is shown as connected to the bearing plate at one end thereof. A plurality of transmission units are disposed rearwardly of the panel plate, each in connection with its own operating manual, and since all are alike a description of but one will sufiice.

Through the slot I! of the panel plate is forwardly projected a stem which is extended from one end of a slideplate it having at its opposite end a laterally turned flange 22 with an elongated slot 23 therethrough. Two aligned slots 24 are also provided in the slide plate adapted to receive therethrough a pair of headed pins 25 which are extended laterally from an elongated mountin plate i one of whose edges is provided with a pro- J'ecting hook 21 and an ear 28 the latter adapted to abut the back face of the bearing plate to provide for the mounting plate a stop which is operative when it has advanced to an extreme forward position. A coiled spring 29 which connects at one end with the hook 2'! and at its other with an eye 30 on the. panel plate serves to maintain the mounting plate yieldably in the position shown in Fig. l where its ear may engage with the bearing plate.

At the rear end of the mounting plate is laterally extended a pair of spaced lugs 3| affording abutments adapted to rest against and within notches 32 at one end of two companion clamping bars 7 and 7c whose upper and lower edges at the forward end are formed with oppositely inclined cam surfaces 34 which terminate, by preference, in dwells 35 adjacent stop shoulders 36. A hole 31 is formed through the mounting plate slightly forwardly of the two lugs 3| and equidistant therefrom. adapted to receive a stud 38 one end of which is headed at 39 (see Fig. 2) to abut a shim or washer 40 upon the mounting plate side that is opposite to that from which the lugs 3| are extended. This stud is shouldered to extend fixedly outwardly from the mounting plate to support fast thereon a crescent plate Z having a pair of rearwardly disposed horns 4B which lie above and below the upper and lower edges, respectively, of the mounting plate. Outside of the crescent plate the stud is again shouldered, as at 47, to provide a spacer against which may be rested the two clamping bars 9 and- 7c which, near their rear ends, are formed with a pair of facing semicircular gripping notches 48 adapted to receive the stud between them. A head 43 upon the proximate stud end completes the mountingcrescent plate and clamping bar assembly. The cammed ends of the clamping bars are adapted for extension forwardly through the slot 23 of the flange 22 when the notches 32 at the rear ends of these bars are interfitted with and engaged by the lug abutments 3 I. The effect of such an assembly is to constitute a compound clam formed of two bars each of which is a lever of the second class with the stud, against which opposing pressures are exerted, acting as the weight.

The mounting plate is provided at its rear end with an extension piece 50 which is slidably received within and supported by a slotted bar m that is extended between the supporting plates 9.

The mounting plate is thus slidably supported at its extreme rear end as well as at an intermediate point where it traverses the slotted bearing plate. Its forward end lies alongside of the slide plate 20 to which it is secured by the pins 25 and slot 24 connection and held frictionally, but adjustably, in a fixed position relative thereto by the opposing pressures proceeding from opposite ends of the slot 23 acting upon the cam surfaces 34. The slide and mounting plates are, therefore, joined in unitary relation and, in response to pulling force of the spring 29, are normally maintained in a forward position with the ear 28 abutting the bearing plate ,1. The forward end of the stem 20 may carry a manual in the form of a push button 5| by which the entire slide-mounting plate assembly may be pushed in to perform turning operations upon the condenser shaft b in a manner that will presently be explained.

In mesh with a pinion n fast on the tuning shaft 2) is an arcuate rack 0 carried on an arm 52 which is affixed to a stub shaft p that is rockably mounted on the supporting plate g in line with the extension piece 58. Also carried fast on the stub shaft is a fan plate q fixedly supporting rearwardly of its axis of movement one end of a tilting bar r through which are slots 53 for the passage of the several extension pieces 50. This bar which extends equidistantly above and below the stub shaft 10 is adapted to be swung about its axis, together with the two fan plates (only one of which is shown) upon which it is supported. This takes place whenever one horn of a crescent plate engages with the tilting bar in advance of the opposite horn whose later engagement acts as a stop to limit the swinging movement of the bar to a predetermined distance. Each such change in the position of the tilting bar produces a corresponding change in the position of the tuning shaft 1) because of the motion that is transmitted through the rack and pinion o and n, respectively. If there be any change in the rotative position of the crescent plate, however, one of its horns will advance or recede, relative to the other and to the tilting bar 7* so that, in the ensuing engagement therebetween, the tuning shaft will be turned to a selected position, depending upon the rotative adjustment of the crescent plate relative upon its mounting.

A correct and dependable setting of each crescent plate requires only that a pulling force be applied to the push button manual 5| to shift the slide and mounting plates relatively in a direction which will relieve the pressure upon the cammed surfaces of the clamping bars 7' and 70. When this has taken place, the crescent plate is unlocked. so as to be free for adjustment to any desired rotative position. Such an adjustment is made automatically by rotating the full-range control knob l5 until a selected station is perfectly in tune, and then pressing in the push button manual to the point that both horns of the crescent plate are engaged with the tilting bar r in its newly adjusted position; the crescent plate will thereupon adjust itself to a like rotative position, and continued inward movement of the slide-mounting plate assembly will restore pressure to the clamping bars so as to lock the crescent plate in its finally adjusted position. The friction lock thus maintained is amply strong for all normal operating conditions. No tools are required for the adjustments just described, and all manipulations are made from a point forwardly of the front panel plate, thus conducing to convenience and ease in these operations.

In the adjustable transmission unit illustrated in Figs. 1-5 the principal parts are in the form of plates which may be accurately and conveniently produced from sheet metal as by stamping operations. For the production of the principal parts of the adjustable transmission units shown in Figs. 6-20 a similar method of production may be employed although they may be formed with perhaps greater advantage by die casting operations. These constructions which will now be described are each adapted for incorporation in a radio receiving set having a tuning shaft b together with a full-range operating means therefor, such as the shaft [5 and control knob 16.

The improved transmission unit of Figs. 6-17 utilizes certain associated operating means such as an endless flexible ribbon 55 which is extended around the tuning shaft b and also a stud 56. The shaft and stud are formed each with a flat 5'! on their respective surfaces, and the ribbon is connected fast to each such fiat as by means of a pin 58. The stud is frictionally locked in a frame s with which is associated a second frame it, both shown clearly in the perspective views of Figs. 9 and 10. The frame s comprises a pair of spaced parallel upper and lower bars 60 and SI each extended from a head plate 62 wherein is formed a slot 63. The opposite ends of each pair of bars is connected by a vertical cross bar 64 each of which supports one end of a pair of spring arms 65 having between them a con tractable circular opening 59 extending through nearly 360. The free ends of these arms which are rounded or beveled at 66 lie within notches 61 formed in the bars 50 and GI. Cooperating lugs 68 and 69 formed on the arms and bars, respectively, provide interengaging shoulders.

Each of the frames s supports one of the studs 56 at whose opposite ends the diameter may be slightly reduced for reception within the circular openings 59 which thus constitute split bearings for the stud. The arms 65 tend normally to spring outwardly to the position shown in Fig. 9 so that the supported stud is free to turn within the bearing thus provided by the circular open- The cooperating inner frame t which is adapted to be fitted within the outer frame s normally remains immovable therewithin. The inner frame comprises a head plate 10 from which are extended two pairs of parallel bars H and 12, the former above the latter. Connected with the head plate is a reciprocable bar 13 adapted for sliding reception within the slot 63 of the head plate 62 of the outer frame s, the other end of the reciprocable bar being fitted with a push button manual such as those already described. When the two frames are interfitted, the bars H and 12 are disposed to the inside of the bars 60 and 6|, respectively. Cam blocks I4 are provided at the free ends of the bars H and 12, being laterally extended to lie within the notches 51 opposite the rounded or beveled ends 66 of the spring arms 65. These cam blocks are adapted, when advanced relative to the spring arms, to force the latter inwardly thereby contracting the circular opening 59 to exert a clamping force upon the supporting stud 56 sufiicient to lock it firmly against rotative movement. When the cam blocks are withdrawn from wedging engagement with the spring arms, the latter are free to expand outwardly again, whereupon the supported stud is released for further rotative adjusting movement, if desired.

With such a construction the tuning and adjusting operations are the same as that previously described for the transmission unit of Figs. 1-5. It will be noted that the tuning shaft is extended freely between the upper and lower bars of the two frames 8 and t which, in normal operation, reciprocate in unison, without relative movement therebetween. In all such movements, however, the two frames may occupy different positions relative to the condenser shaft, as clearly indicated in Figs. 11-17. In Fig. 11 the transmission unit is represented as in a normal position of rest with the tuning shaft in the rotative position which has been assumed in response to operation of the associated push button manual. In each of Figs. 11-12 the spring arms are shown as contracted so that the supported stud is locked against rotative movement. The upper and lower runs of the flexible ribbon 55 are shown as slack in Fig. 11. In Fig. 12 the reciprocating bar has been pushed in a distance sufiicient to tighten the upper run of the ribbon, and in response to continued movement the taut upper run of the ribbon will produce a rotation of the tuning shaft b in a counter-clockwise direction to the point that the lower run is also taut. Another locked position of the stud is shown in Fig. 13 wherein the lower run of the belt is taut consequent upon operation of some manual connected to a transmission unit other than the one illustrated. If the transmission unit of Fig. 13 be advanced, as in normal operation, its forward movement will produce a clockwise rotation of the tuning shaft to the position shown in Fig. 14 where the upper run of the belt is also taut.

Assuming that a new setting is desired for one of the tuning manuals, the first step is the application of a pulling force thereto. When th s takes place the inner frame is moved outwardly with respect to the outer frame so that the head of one engages with the head of the other. The cam blocks being then retracted, the spring arms 65 are free to expand outwardly whereby to release all clamping pressure upon the stud. Both runs of the belt are then slack (see Fig. 15) and if the full-range tuning control be then operated to place the shaft 17 into resonance with a desired station, the slack in one or the other of the belt runs will be somewhat taken up. Having set the tuning shaft to the desired position, pressure is then applied to the push button manual for shifting the inner frame If outwardly relative to its enclosing frame s. In this movement the stud, while still free within the spring arms, is rotated as both runs of the belt become taut (see Fig. 16), and thereafter the inner frame advances relative to the other so that the cam blocks ride up along the beveled ends of the spring arms to restore the clamping pressure to the stud whereby it is again locked immovably within the frame. Each subsequent operation of the associated push butt-on manual will thereafter, of necessity, reciprocate the transmission unit to produce a turning movement of the tuning shaft to the position predetermined by the setting last completed.

Referring now to Figs. 18-20, I have here shown an outer frame it within which is fitted an inner frame, each of U-shape, and generally the same as the frames shown in Figs. 9 and 10. The outer frame is formed with a pair of upper and lower bars and 8|, respectively, joined at one end to a common head plate 82, the opposite ends of each pair of bars being connected by a vertical web 83 wherein are openings forming bearings for opposite ends of a stud 84 mounting in its center region a bushing 85 having a fiat 51, the bushing ends being spaced from the frame bars. Fitted upon the stud 84, between each bushing end and the adjacent bars, is a spring washer 36 in cooperation With beveled ends 8'! of upper and lower bars 88 and 89, respectively, extending from a common head plate 99 of the inner frame 12. Connected with and extending from the head plate of the inner frame is a reciprocating bar 9| whose outer end is equipped with a manual preferably in the form of a push button (not shown). The two washers, when advanced against the stud ends, act as brakes to prevent rotation of the stud.

When the heads of the two frames are in substantially adjacent relation (as shown by full lines in Fig. 18), the beveled ends 8'! of the bars 88 and 89 are sufiiciently withdrawn from the stud 84 to relax their opposed lateral pressures against the two washers 86. In this condition of release the bushing 85 is free to rotate. An endless flexible ribbon 55 extends over and around the stud and tuning shaft, being fastened to each, as alread explained. If the push button be advanced, however, the inner frame moves relatively to the outer frame so that the beveled ends 87 of the bars 88 and 89 exert lateral pressures against the spring washers in suflicient force to frictionally lock the drum against rotation relative to the frames. As a result, motion originating at the manual may be utilized to render the drum either fast or loose, as required, for setting of the tuning shaft b in a desired rotative position, all as previously described in connection with Figs. 6-17.

The manufacturer of a radio receiving set of the push button type must choose between (1) a large number of such manuals to afford a greater selection of stations, or (2) a smaller number of such manuals with a lesser selection of stations available. While the latter ofi'ers economies, it may not meet the wishes of the owner who is desirous of having a relatively large number of stations each available by push button tuning. Assuming that he is dissatisfied with the original setting, it is necessary, in most cases, to obtain access to the interior of the cabinet, and then proceed with one or more tools to eifect a desired resetting of some or all of the manuals relative to the tuning shaft. cases this is a job for an expert and consequently the owner is deterred from taking this step.

The adjustable transmission unit herein disclosed will obviate all such difficulties. t permits the use of a relatively few push button manuals, and the setting of any of these manuals to be changed in just a few moments without (1) access to the interior of the chassis and (2) the employment of any tools for the operation. The simple expedient of first pulling the manual to be re-set, then manipulating the usual full-range tuning control for movement of the tuning shaft to the desired position, and thereafter pushing the manual, is all that is required. These operations are so simple that they can be attended to by almost anyone. In fact they are so easy as to encourage frequent re-setting of any of .the manuals in response to any desire for a change, so that the provision of just a few push buttons each in operative connection with one of my improved transmission units, will satisfactorily meet all the usual requirements.

The constructions herein described are alike in principle of operation, and they all have in commen the feature of two relatively movable ele- In most ments each adapted, in cooperation with. the other, to releasably lock an adjustable third element which is in connection with the tunin; shaft so as to permit a change in its operative relation to the associated manual, the lock comprising in each case a clamping device which exerts opposed equalized forces which allows the affected parts to continue in balanced relationship under all conditions. As previously indicated, my invention may be embodied in different forms, those shown and described being merely representative of many.

Iclaim:

1. In a radio receiving set having a tuning device and means for operating the tuning device including a manual, a, transmission unit between the manual and the tuning device comprising a pair of relatively, slidable elements and a third rotatively adjustable element, a split bearing carried by one of the slidable elements affording support for the rotatively adjustable element, cam

means, operable by relative movement between the slidable elements, acting upon the split bearing to tighten or loosen its engagement with the rotatively adjustable element to permit adjustment of the latter to a selected rotative position when the bearing is in loose condition, and an operating connection between the adjustable element and the tuning device.

2. In a radio receiving set having a tuning device and means for operating the tuning device including a manual, a transmission unit between the manual and the tuning device comprising a pair of relatively slidable elements with one of which is associated a split bearing, a rotatively adjustable element mounted within the split bearing, means in connection with the slidable elements for releasably tightening the split bearing to secure the adjustable element in a selected rotative position, and an operating connection between the adjustable element and the tuning device.

3. In a radio receiving set having a tuning device and means for operating the tuning device including a manual, a transmission unit between the manual and the tuning device comprising elements connected for relative sliding movement, an element mounted for rotative adjustment, a split bearing supporting the adjustable element, means associated with the sliding elements for tightening the split bearing to lock the rotatively adjustable element in a selected fixed position, and means extending from and operated by the rotatively adjustable element for moving the tuning device.

4. In a radio receiving set having a tuning device, a control means for moving the tuning device to any selected position through its entire operating range, and other means for moving the tuning device to a single preset position comprising a manual, a rotatively adjustable element having an operative connection with the tuning device adapted to transmit movement thereto. a split bearing wherein the adjustable element is mounted, and a, pair of relatively slidable elements with one of which the split bearing is fixedly associated, and means operated by movement of the slidable elements relative to each other in one direction to tighten the bearing whereby to lock the adjustable element against rotation within its mounting and, when operated by movement of the slidable elements relative to each other in the opposite direction, to loosen the bearing whereby to release the adjustable element for rotation, and a connection between one of the slidable elements and the manual adapted to transmit motion in either of two directions, the adjustable element, when released for rotation, being automatically reset in any selected position in response to sequential operation of the control means and manual.

5. In a radio receiving set having a tuning device, a manual movable in two directions, and a transmission therebetween comprising a rotatably adjustable element, a tensioned split bearing in which the element is mounted for rotation, the bearing tension exerting its force in a manner which normally frees the element for rotation, and means in connection with the manual operatively associated with the bearing adapted, in response to one movement of the manual, to force a compression of the bearing at the split whereby to lock the adjustable element against rotation from a desired position.

6. In a radio receiving set having a tuning device, a manual movable in two directions, and a transmission therebetween comprising a rotatably adjustable element together with a mounting therefor, a pair of friction brakes movable parallel with the axis of the adjustable element to engage opposite faces thereof, and means in connection with the manual operatively associated with both brakes adapted, in response to one movement of the manual, to advance both brakes simultaneously with equalized force against opposite faces of the adjustable element to lock the same against rotation and, in response to a second movement of the manual, to release both brakes to free the adjustable element for rotation to a desired position.

ALBERT S. WELLS. 

